[UNOMI-897] Groovy data corruption and performance fixes

[sergehuber]

UNOMI-897: Fix data corruption and performance issues in GroovyActionDispatcher

• Fixed data corruption issue by removing shared GroovyShell instance with separate script instances for separate variables
• Improved performance by moving to pre-compilation of scripts to avoid on-the-fly and previously systematic compilation of Groovy scripts
• Add ScriptMetadata class for script management and caching

[Fgerthoffert]

@jayblanc or @jsinovassin would you mind reviewing this PR ?

[Copilot]

Pull Request Overview

This PR addresses data corruption and performance issues in the Groovy action dispatching by removing the shared GroovyShell, introducing pre-compilation and caching of scripts, and updating the public API and tests accordingly.

• Removed shared GroovyShell in favor of thread-safe, per-script compiled classes.
• Added ScriptMetadata for hash-based change detection and caching.
• Updated service interface and integration tests to use getCompiledScript and metadata APIs.

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
itests/.../GroovyActionsServiceIT.java	Updated integration tests to call getCompiledScript instead of legacy APIs.
GroovyActionsServiceImpl.java	Refactored core service to precompile scripts, manage ScriptMetadata, and remove shared shell.
GroovyActionsService.java	Extended service interface with new methods (getOrCompileScript, getCompiledScript, getScriptMetadata).
ScriptMetadata.java	Added immutable class for storing compiled script metadata and change detection.
GroovyActionDispatcher.java	Modified dispatcher to instantiate and execute precompiled Script classes.

Comments suppressed due to low confidence (3)

extensions/groovy-actions/services/src/main/java/org/apache/unomi/groovy/actions/services/GroovyActionsService.java:92

• The return type is broader than other methods. Consider narrowing this to Class<? extends Script> for consistency with getCompiledScript.

    Class<?> getOrCompileScript(String id);

extensions/groovy-actions/services/src/main/java/org/apache/unomi/groovy/actions/services/GroovyActionsService.java:106

• [nitpick] The parameter name 'id' is inconsistent with other methods that use 'actionName'. Consider renaming it to 'actionName' for a consistent API.

    Class<? extends Script> getCompiledScript(String id);

extensions/groovy-actions/services/src/main/java/org/apache/unomi/groovy/actions/services/impl/GroovyActionsServiceImpl.java:180

• New pre-compilation logic introduced here should be covered by unit tests to verify correct caching behavior and error handling.

    private void preloadAllScripts() {